The recent introduction of WiMAX technology promises to further increase the proliferation of wirelessly-equipped devices. WiMAX (Worldwide Interoperability for Microwave Access) is an Institute of Electrical and Electronics Engineers (IEEE) standard, designated 802.16, with the 802.16e being the current version of the standard (the terms “IEEE 802.16,” “IEEE 802.16e,” and “WiMAX” may be used interchangeably herein). WiMAX provides a robust mechanism for wireless communication between base stations and subscriber stations. In particular, WiMAX is designed to provide fixed, portable or non-line-of-sight service with a potential range of 6 miles, a potential bandwidth on the order of 40 megabits per second, and superior quality of service and security.
WiMAX chipsets that provide for communication in accordance with the WiMAX protocol are becoming increasingly prevalent as standard or optional equipment not only in traditional wireless communications devices, such as cellular phones and personal digital assistants, but also in devices that, heretofore, were not used for access to telephony networks. These devices include portable music players, entertainment devices such as game players, automobiles, domestic appliances and so on. It is expected that by the year 2009 there will be in excess of 100 million devices in use that have WiMAX chipsets in them. Thus, a virtual explosion of the number of WiMAX devices is expected to occur in the near future.
In order to engage in communications, the client and the WiMAX base station synchronize on both the downlink and the uplink. Thus, when initiating a WiMAX communication session, the client secures a downlink connection to receive data from the WiMAX network, as well as an uplink connection to send data to the WiMAX network. Accordingly, a WiMAX base station periodically broadcasts a downlink coding descriptor (DCD) and an uplink coding descriptor (UCD), which include information that can be used by the mobile to synchronize with a base station on both the downlink and the uplink, respectively. The DCD and UCD, which may each generally be referred to as a coding descriptor (or collectively referred to as coding descriptors), are broadcast messages. Thus, the DCD and UCD are made available to any client within range of the base station that is broadcasting these coding descriptors.
Under current practices, a WiMAX base station transmits the DCD and UCD periodically, by from time to time including a DCD and a UCD in a WiMAX frame. Thus, a DCD and a UCD are not necessarily included in every WiMAX frame. The repetition frequency with which the DCD and UCD are broadcast by a WiMAX base station (i.e. how often the base station includes the DCD and UCD in a WiMAX frame) is configurable. For example, a base station may, by default, transmit a DCD and UCD every 25 milliseconds. However, a service provider may configure the base station to transmit the DCD and UCD more or less frequently than every 25 milliseconds, for instance.